Method and apparatus for molding concrete pipe



C. M. SNYEF? Apr 3s, w33.

METHOD AND APPARATUS FOR MOLDING CONCRETE PIPE Filed May 27', 929 2Shams-Sheet l @ggf H15 awa/M4495 Apri 1s, 1933.

FiledA May 27,' 1929 2 ShebS-Sheet 2 zzv Ewan/toe 'l 'I HisduawmgsPatented Apr. 18, 1933 CLAY M. sNYnEa or ATLANTA, GEORGIA, AssreNoR ToVoENTRI'rUGAnMAcHTNE COMPANY, or` ATLANTA, GEORGIA METHOD AND APPARATUSrca MoLnINe coNcTtrzTri rire Application led May 27,'

rlhis invention relates to concrete molding and particularly to animproved method and apparatus for producing concrete pipe.

One object of thev invention is to produce a method and apparatus withwhich the pipe section may be quickly produced while, at the same time,the material constituting such pipe sections will be of uniform densityor compactness.

A further object is to utilize centrifugal force in placing andcompacting the concrete in the form, no pressure from any other sourcebeing necessary.

Another object is tov provide means for substantially uniformly feedingthe concrete to the mold at a rate dependent upon the speed at which therotor, by which the material is centrifugally compacted, isrotated;Inthe present apparatus as has been said,

the material is compacted by centrifugal force generated by a rotor thatis-initially inserted in the lower end of a pipe form and as theconcrete is molded in said form the latter is adapted to be movedlongitudinally away from the rotor. This movement continues until therotor has assumed a position substantially free of the mold form.

It will be appreciated that as they concrete is molded in the form theweight thereof gradually increases and in view of this the presentinvention contemplates means for' gradually increasing the resistancethat must be overcome in order to permit the form to move relativelyaway from the rotor.

Another object is to simplify the apparatus and method, the apparatusconsisting of what is believed to be a minimum number of parts, all ofwhich are of simple and sturdy construction so that the maintenance andup- 40 keep thereof is comparatively inexpensive. The present apparatusis also portable, there= by permitting the pipe to bev produced at thepoint of use. Y

lVith these and other objects in view, the invention consists in certaindetails of construction and ycombinations yand arrangements of parts,all as will hereinafter be more fully described and the novel featuresthereof par# ticularly pointed out'in the appended claims.

ln the accompanying drawings, illustrat- 1929; Serial No. 366,227. ingone form of apparatus for carrying out the proposed novel method: f

Figure l is a side elevational view, por-V tions of the supportingstructure being brokenaway for purposes of illustration, and the partsbeing shown in they positions they initially. occupy in producingasection of pipe. Y t F ig. 2 is a view similar to Fig. l, butshowsection of pipe partially completed. n

Fig. 3V is a front elevation with the linished .pipe and form shown insection. f

Fig. t is a cross-section of' a finished pipe section. l y

Fig. 5 is a plan viewof the form support. v,In accordance with thepresent method the pipe is made in a mold or form into which a rotor isadapted to be initially inserted, the form being yieldingly'heldinvproper posi- 70 tion relative to said rotor.` Concrete is delivered tothe rotor within the form and dis.- tributed and compacted. uniformlytherein by centrifugal force developed by the rotary movement of therotor. The form, except 75 for the bell end ofthe pipe,`consistjs ofonly one wall,the periphery of the rotor constitutingthe other or innerV wall of theform and as the concrete is compacted in the space betweensaid rotor and outer wall of the form, 80 the form is gradually movedaway from the rotor until the latteris practically withdrawn therefrom.'c p Y In carrying out the preferred method, the form is supported on amovable pallet and A as the pipe is built up in said form the weight vonthe pallet gradually increases. For this reason the pallet and' form aresupported in proper position relative tothe-rotor bycounter-balancemeans of atype iwhereinthe weight of the counter-.balancewill be gradually increased in accordance with the increasing weight 'ofthe pipe being formed. To insure uniform action during theroperationofthe apparatus the drive mechanism for l the rotor is also utilized forgoverning the feed of concrete vor material to the form. i Y Thepreferred form of apparatus for carrying out this method comprises Vasupporting frame work of uprights lO-and braces 11, said lng only aportion of thev apparatus withy a 60 uprights serving as guides for aplatform 12 which has cables 13 attached to opposite sides thereof.These cables 13 eXtend over pulleys 1A journaled in the uprights 1() andat their free ends have attached thereto counterbalance means preferablyin the form of a body 15a and a chain 15b. Chain 15b has one endsupported from the frame 10 so that as the body 15a is raised it willsuccessively, so to speak, pick up and support additional links of thechain for purposes which will presently appear. Journaled in theplatform 12 is a series of rollers12a to facilitate movement of pallets,one of which is indicated at 17, onto and ofin of said platform. Thesepallets are adapted to have placed thereon the forms for the pipesections to be produced, said forms constituting an outer shell 17a andan inner member 18. Outer shell 17 a corresponds in length tothe lengthof the pipe section to be produced and is flared at one end whereby, inconjunction with the inner mold member 18, the bell end of the pipesection may be formed. A pallet containing one ofl these forms is placedon platform 12 and, because of the weight of the counter-balance means,is raised to the position shown inV Fig. 1, wherein the rotor 19 fordistributing` the concrete in the form is located just above the topedge of form member 18. With the parts in the positions shown in Fig. 1,concrete is deposited in the form and rotor 19 driven at the desiredspeed in a counter-clockwise direction. On the upper surface of saidrotor there are a plurality of radially disposed vanes 20 so that `asthe concrete falls on the upper surface of said rotor it is distributedradially thereof by centrifugal force. VNot only is it distributed bythe centrifugal force generated by the revolving head, but it is alsocompacted in the space between the inner and outer shells 17 a, 18,until that space is filled after' which the material which iscontinuously supplied to the form gradually fills the space betweenshell 17a!l and the periphery of the rotor. As this latter space isfilled, the material, indicated atC, builds up until it reaches a pointwhere it is engaged by vanes 20a on the periphery of the rotor, vanes20a being continuations of vanes 20, if desired. As will be understood,as the concrete is compacted by centrifugal force in the form, the vanes20ct gradually depress the support 12 against the pressure exerted bythe counter-balance means, this operation continuing until rotor 19protrudes'above the upper end of shell 17a, at which time the section ofpipe is completed. A section of pipe `partially completed is illustratedin Fig. 2, and a completed section in Fig. 3. The movement ofthe formrelatively away from the rotor is smooth and constant due to the slightrestraining action of the counter-balance means. In this way, theposition of the form is automatically coordinated with the placement ofconcrete, the vanes acting always upon concrete previously placed andcompacted by the action of centrifugal force. In actual operation thevanes 20a are usually about an inch below the point where the concreteleaves the upper surface of the rotor, thus eliminating any tendency ofthe concrete to pile up Vand clog the vanes 20. It will also beunderstood that after one pipe section'is completed another pallet, witha form thereon, is placed on the carriage or support 12 after thepreviously formed pipe section and its form have been removed. The

smoothness of the movement of the carriage and form awayfrom the rotoris assured by reason of the character of the counter-balance meanspreviously described. That is, when the carriage is in its uppermost orinitial position, most of the chain 15b is suspended Y from the support10, but as the pallet and carriage are lowered, additional linksof thechains are picked up and suspended from the ends of the cables 13. Inother words, as the weight of the concrete in the form increases, theweight of the counter-balance increases, thereby securing a uniformityin the movement of the carriage away from ythe rotor during theproduction of the entire pipe'section. A further advantage ofV co'm-29.5

pacting material by the action of centrifugal force is that the width ofvanes 20al need not equal the thicknessof the walls of the pipe sectionso that, if desired, reinforce elements may only being necessary thatsuch reinforce elementsbe positioned in the forms at a point beyond theouter edges of the vanes 20a.

The rotor 19 is mounted on a shaft 21 eX- tending through a chute 22 bywhich the concreter is delivered to the interior of the form. rlhematerial, concrete, is preferably delivered from a hopper 23 by anendless traveling conveyor 24'whose rate of movement is governedentirely by the rate of movement, of the rotor, as will be pointed out.Shaft 21 is journaled in cross members 25 of the supporting frame,thrust collars 26 on the shaft engaging said members 25. At

Vits upper end shaft 21 is provided with a pulley 27 to which power maybe supplied from any suitable source..` Mounted on shaft 21 is a beveleddrive wheel 28 adapted to be engaged by a friction wheel 29 which ismounted on a shaft 30 journaled in bearings 31 in a sleeve 32eccentrically arranged in a boX 33 supported from the cross members 25.Also mounted on shaft 30 isV a pulley 34 which is'connected to a pulley35 by a belt 36, pulley 35 being mounted on a shaft carrying one of therollers for the feed belt or endless conveyor2f. Sleeve 35 is capable ofbeing rocked in boX 33 by an operating lever 37 so as to move frictionwheel yor disk 29 into or out of engagement with the drive vthe speed ofthe rotor,

wheel 28 when and as desired. With this arrangement the rateof movementof the endless conveyor 24 is entirely dependent upon the speed ofrotation of'rotor 19.

Vith the present apparatus'there are a comparatively small number ofparts, `all of simple construction so thatthe initial cost of theapparatus as well as its maintenance and upkeep is exceedingly low. Inproducing pipe with the present apparatus and method,

easily transported wherever desired so that the pipe can be manufacturedvat the point of use. It is also believed that the uniformity of densityof the finished product is aided by reason of the fact that theapparatus and method include means for co-ordinating the feed ofmaterial with the rate of movement of the rotor as well as meansforgradually increasing the resistance offered to thel movement of the formsupport away from `the rotor as the weight of the pipe being formedgradually increases. 3

It is of course understood that the concrete is actually placed andcompacted by centrifugal force, said placement and compacting being' theresult of one mechanical effort. It

might be said that the compacting is really the result of impact betweenthe material being forcibly thrown into place, and the materialpreviously placed. Y

The density of any joint or section of pipe being molded may be variedby varying as it is upon said speed of rotor and the impact produced bythe speed of material leaving the rotor theY density depends, and notupon the action of the compensating counterweights as might beconstrued.

The monolithic construction of the completed section or joint of. pipeis in itself unique, as this is accomplished in one continuousmechanical action, and assures an evenly compacted anddense pipe sectionthroughout. Y

What I claim is:

l. In a concrete pipe making apparatus, the combination of a form,ineansfor compacting concrete in said form, said form being movable away fromthe compact-ing means by the pressure of concrete placed in the formagainst said compacting means, and means for gradually increasing theresistance offered the movement of said formr as the weight of theconcrete placed in the form increases.

2. In a concrete pipe making apparatus, the combination of aform,means'for com'- pacting concrete in said form, means for` yieldinglysupporting' the formin cooperativerelation with respect to saidcompacting means, said form being movable away from said compactingmeans by the pressure of concrete in the form against the compactingmeans, and meansfor increasing the resistance oifer-ed the movementofthe form away Afrom said compacting means, as the weight of theconcrete in the form increases.

In a concrete i e makin ai aratus P P :s l P a the combination of aform, a. rotor having a cross section conforming to the inner surface ofthe pipe tojbe produced and adapted to be inserted lin said .forin,radially 4 disposed vanes on said rotor, a second set of yvanes-on theperiphery of said rotor, andv means for delivering concreteV to lsaidform, saidform being adapted to be moved longitudinally away from saidrotor by pressure of concrete placed in the form against said second setof vanes. Y

4l. In a concrete pipe making apparatus, the combination of a form,arotor having a cross section conforming to the inner surface of thepipe to be produced and adapted to be inserted insaid form, radiallydisposed vanes on said rotor, a second set of vanes on the periphery ofvsaid rotor, and means for delivering concrete to said form, said formbeing adapted to be vmoved longitudinally away from said rotor bypressure of concrete placed in the form against said second set ofvanes, the width of the Vvanes of said second s-et being less than thethickness of the pipe wall. Y l

5.,In a concretev pipe making apparatus, the combination of a form, arotor having a cross section conforming tothe inner sur-V face of thepipe to be produced and adapted to be inserted in said form, and meansfor delivering concrete to said rotor at a rate dependent upon the speedof rotation of said rotor, said formbeing adapted to be movedlongitudinal'lyaway from said rotor by the pressure of concrete placedtherein against said rotor. Y

6. -In aconerete pipe makingv apparatus, the'combination of a form arotor having a cross section conforming to the inner surface of the pipeto be produced and Aadapted to bev inserted in said fornizradiallydisposed vanes on said rotor a second set of-vanes on the periphery ofsaid rotor, a shaft on Ywhich lsaid rotor is mounted, means operativelyeon- Y nected to said shaft for delivering concrete to said form, andmeans for yieldingly resisting "movement of said form longitudinallyaway from said rotor. Y

y 7. Inaconcrete pipe making apparatus, the combination of a form, arotor having a' cross section'conforming to the inner surface of thepipe to be produced and adapted to be 'dii Sie

inserted in said form, radially disposed vanes on said rotor, a secondset of vanes on the periphery of said rotor, a. shaft on which saidrotor is mounted, means operatively connected to said shaft fordelivering concrete to said form, means for yieldingly resistingmovement of said form longitudinally away from said rotor, and ,meansfor gradually increasing the resistance offered the movement of the formaway from said rot r, as the Weight of concreterplaced in said formincreases.

8. In a concrete pipe making apparatus, the combination of a verticallymovable form, means for placing and coinpacting concrete in said form,means for yieldingly forcing the form upwardly so that the growing topedge of the pipe being formed bears continuously against said placingmeans, said lastspecified means including a counterpoise accuratelycompensating for the increase in the weight of the pipe as it is beingformed, thereby providing movement of said form directly proportional tothe rate of formation.

9. In a concrete pipe making apparatus, the combination of a form, arotor having a cross-section conforming in size to the inner surface ofthe pipe to be produced and adapted to be inserted in said form,radially disposed vanes on said rotor, a chute for delivering concretemix solely to the inner portions of said vanes well inwardly from theperiphery of the rotor and the outer ends of the vanes, and means forturning said rotor and the vanes mounted thereon at such a high rate ofspeed that the mix deposited at the inner ends of the radial vanes iscentrifugally hurled from the rotor and compacted radially against theinternal surface of said form.

10. In a concrete pipe making apparatus,l

the combination of'a form, a rotor having a cross-section conforming insize to the inner surface of the pipe to be produced and adapted to beinserted in said form, radially disposed vanes on said rotor, a chutefor delivering concrete mix solely to the inner portions of said vaneswell inwardly from the periphery of the rotor and the outer ends of thevanes, means for turning said rotor and the vanes mounted thereon atsuch a high rate of speed that the mix deposited at the inner ends ofthe radial vanes is centrifugally hurled from the rotor and compactedradially against the internal surface of said form, and means foraxially moving the rotor relatively to the form to smooth the innersurface of the pipe as it is formed.

` 11. In a concrete pipe making apparatus,

the combination of a form, a rotor having a cross-section conforming insize to the inner surface of the pipe to be produced and adapted to beinserted insaid form, radially disposed upstanding vanes on said rotor,means for delivering concrete mix solely to the center portion of therotor and the innermost portions of the vanes, and means for turningsaid rotor and the vanes mounted thereon at such a high rate of speedthat the mix fed to the inner portions of the radial vanes iscentrifugally hurled therefrom and compacted radially against the innersurface of the form.

12. The method of forming concrete pipe which comprises providing anexternal form to which the outer surface of the pipe is to conform,feeding concrete mix to the center of said form completely out ofContact With the form yand subsequently radially projecting anduniformly distributing the centrally placed concrete mix by centrifugalaction at such velocity as to completely compact it against said innerform surface without troweling.

13. The method of forming concrete pipe which comprises providing anexternal form to which the outer surface of the pipe is to conform,slowly feeding concrete mix into the center of the form completely outof contact With the form and progressively radially projecting saidconcrete mix, as fed, and uniformly circumferentially distributing thecentrally fed concrete mix by centrifugal action at suoli velocity as tocompletely compact it against said inner form surface Withouttroweliiig. Y

14. The method of forming concrete pipe which comprises providing anexternal form to which the outer surface of the pipe is to conform,slowly feeding concrete mix into the center of the form completely outof contact with the form and progressively radially projecting saidconcrete mix, as fed, and uniformly circuinferentially distributing thecentrally fed concrete mix by centrifugal action at such velocity as tocompletely compact it against said inner form surface without troweling,and automatically progressively moving said form axially at a ratedirectly proportional to the rate of pipe formation.

CLAY M. SNYDER..

